[IEC][SEBA][PONSim] ONU authentication not working

So far only seen on a virtual POD running o a ThunderX2, but it might be unrelated.

The observable issue is that ONOS does not detect any authentication request from the RG. However, the RG passes packets to the ONU, which in turn seems to successfully pass them the OLT through Calico. One arrived at the OLT, they should probably be passed to the Aggregation switch (emulated by the mininet pod using OpenVSwitch), although I'm not 100% sure. Comparing against a working setup, it's not yet definitive.